Start by preheating your oven to 400°F (205°C). While the oven warms up, arrange a single layer of saltine crackers on a standard cookie sheet lined with parchment paper or foil. You’ll need about 48 crackers to cover the surface completely.

In a medium saucepan, combine the butter and brown sugar. Heat the mixture over medium heat, stirring occasionally until it begins to bubble. Once it reaches a boil, set a timer for 3 minutes and let it cook undisturbed. Avoid stirring during this time to ensure the toffee sets properly.

Carefully pour the hot toffee sauce over the arranged crackers, ensuring each piece is evenly coated. Use a spatula to spread it out if necessary. Place the tray in the preheated oven and bake for 5 minutes. Keep a close eye to prevent the toffee from burning.

Remove the tray from the oven and immediately scatter the chocolate chips over the hot toffee-covered crackers. Let the chocolate sit for about 5 minutes, allowing it to soften and melt. Once melted, use a spatula to spread the chocolate into a smooth, even layer.

Sprinkle the chopped pecans and crushed Heath Bar (if using) over the melted chocolate, pressing lightly to help the toppings adhere. Allow the bark to cool completely—this can be done at room temperature or by placing it in the refrigerator for faster setting.

Once fully set, break the toffee bark into irregular pieces and serve. Store any leftovers in an airtight container to maintain freshness.